1. Technical Field
The disclosure generally relates to a light emitting diode with a wave-shaped Bragg reflective layer, and a method for manufacturing the light emitting diode.
2. Description of Related Art
In recent years, due to their excellent quality of output light and high luminous efficiency, light emitting diodes (LEDs) have increasingly been used as substitutes for incandescent bulbs, compact fluorescent lamps and fluorescent tubes as light sources of illumination devices.
A light emitting diode chip of an LED includes a substrate, and a buffer layer, an n-type semiconductor, an active layer and a p-type semiconductor formed on the substrate in that sequence. However, light transmitting from the active layer to the substrate is easily absorbed by the buffer layer and the substrate, thereby decreasing the light emitting efficiency of the light emitting diode chip. In order to prevent light from being absorbed by the substrate and the buffer layer, a Bragg reflective layer is formed between the buffer layer and the n-type semiconductor to reflect light from the active layer. However, the Bragg reflective layer can only reflect light propagating in a direction vertical to the substrate. If light propagates in a direction deviated from the vertical direction, a reflective efficiency of the Bragg reflective layer is reduced.
What is needed, therefore, is a light emitting diode and a method for manufacturing the light emitting diode which can overcome the above-described disadvantages.